U.S. Pat. No. 2,581,514 relates to the production of thio-hydrocarbon succinic acids from maleic acid and a saturated non-tertiary hydrocarbon thiol.
U.S. Pat. No. 3,551,394 relates to the reaction of an unsaturated, high molecular weight substance containing a diene as one of the constituents, and a sulfur compound in the presence of an alkyl hypochlorite additive. The polymers to be reacted are disclosed to include ethylene-propylene-diene terpolymers, and the useful sulfur compounds which are disclosed include thioacetic acid, dithioglycolic acid, mercaptans, thioic acids and dithioic acids. The alkyl hypohalite additive is described to be a reaction aid. The patentee illustrates the alkyl hypohalite-assisted reaction of cis-1,4-polybutadiene (M.sub.L,1+4, 100.degree. C.=42.3) with thioacetic acid to form a rubbery reaction product containing 6.8 wt % S and 9.5 wt % Cl (Example 5). In a comparison, it is taught that no S or Cl was found when the polymer was contacted with the thioacetic acid in the absence of the alkyl hypohalite additive. The halide-containing products of this process are disclosed to be useful as elastomer basestocks, and as oil-extended elastomer basestocks, and some of the products (although which are not further identified) are indicated to be useful as resin blenders, resin processing aids, adhesives, varnishes and lubricating additives.
U.S. Pat. No. 4,080,405 relates to free-radical grafting of one or more polar monomers (e.g., acrylic acid and methacrylic acid) onto polyolefins (e.g., ethylene-propylene polymers), which are in the form of fibrils, powders, granules or films, in the presence of a wetting agent (cationic, anionic or nonionic surfactants, or water-soluble polymers) and a particular additive compound derived from alkanes and containing at least one thiol function. Suitable materials are disclosed to comprise compounds of the formula: HS--R--X, wherein R is saturated bivalent hydrocarbon radical derived from a C.sub.1 to C.sub.18 alkane (optionally carboxylated, hydroxylated or halogenated) and X is a carboxylic, hydroxyl, thiol or halogen group. The additives are said to include thiolactic acid, thiomalic acid, and thioglycolic acid. The grafted polymer products are said have improved wettability properties, as indicated by a critical surface tension of at least 75 dynes/cm, thereby improving their utility in the production of partially synthetic papers.
U.S. Pat. No. 4,080,364 discloses stabilizer mixtures for enhancing the light/air degradation resistance of polyolefins, which stabilizers are obtained by reacting an alpha-olefin with a mercapto-carboxylic acid and a polyhydric alcohol to form a reaction product containing thioether groups and carboxylic acid ester groups. The alpha-olefins have the formula: R.sup.1 C(R.sup.2).dbd.CH.sub.2 wherein R.sup.1 and R.sup.2 are H or monovalent organic groups having from about 1 to about 30 carbon atoms. The mercapto-carboxylic acid and polyhydric alcohol are reacted to form an ester product of the formula: [(HS).sub.m ZCOO].sub.n --R--(OH).sub.p-n.
U.S. Pat. No. 4,226,991 discloses a process for preparing 3-alkylthiopropionic acid esters useful as polyolefin resin stabilizers by reacting a reaction mixture comprising a polyhydric alcohol, a C.sub.6 to C.sub.40 alpha-olefin and beta-mercaptopropionic acid or lower alkyl beta-mercaptopropionate in the presence of an organic peroxide or azonitrile reaction initiator.
U.S. Pat. No. 4,519,925 relates to sulfur-containing compounds useful as lubricant and fuel additives prepared by first reacting a mercaptan with a carbonyl compound to form an intermediate followed by reacting the intermediate with a C.sub.3 to C.sub.40 olefinic carboxylic acid or functional derivative therof.
U.S. Pat. No. 4,600,519 discloses power transmission fluids containing a friction modifier additive comprising an oil soluble C.sub.8 to about C.sub.40 alkyl thio succinic anhydride or acid, which are prepared by the addition of mercapto diacids to the corresponding terminal olefins.
Ashless nitrogen and ester containing lubricating oil dispersants have been widely used by the industry. Typically, these dispersants are prepared from a long chain hydrocarbon polymer by reacting the polymer with maleic anhydride to form the corresponding polymer which is substituted with succinic anhydride groups. Polyisobutylene which has been widely used as the polymer of choice, chiefly because it is readily available by cationic polymerization from butene streams (e.g., using AlCl.sub.3 catalysts). Such polyisobutylenes generally contain residual unsaturation in amounts of about one ethylenic double bond per polymer chain, positioned along the chain.
The polyisobutylene polymers (PIB) employed in most conventional dispersants are based on a hydrocarbon chain of a number average molecular weight (M.sub.n) of from about 900 to about 2500. PIB having a M.sub.n of less than about 300 gives rather poor performance results when employed in dispersants because the molecular weight is insufficient to keep the dispersant molecule fully solubilized in lubricating oils. On the other hand, high molecular weight PIB (M.sub.n &gt;3000) becomes so viscous that conventional industrial practices are incapable of handling this product in many operations. This problem becomes much more severe as the PIB molecular weight increases to 5000 or 10,000.
Increased amounts of terminal ethylenic unsaturation in polyisobutylene (so-called "reactive polyisobutylene") has been achieved by BF.sub.3 catalyzed polymerization of isobutylene. Exemplary of references disclosing these polymers is U.S. Pat. No. 4,152,499. However, such reactive polyisobutylene materials can still contain substantial amounts of unsaturation elsewhere along the chain. Further, it is difficult to produce such reactive polyisobutylene polymers at molecular weights of greater than about 2,000, and, even so, the reactive polyisobutylenes themselves still suffer the above-noted viscosity increase disadvantages as molecular weights are increased.
Other polymers, such as ethylene-propylene co-polymers and terpolymers containing non-conjugated dienes, have been disclosed as suitable polymers for the preparation of ashless nitrogen and ester dispersants.
U.S. Pat. No. 4,234,435, for example, discloses dispersants prepared from polyalkenes, M.sub.n of 1,300 to about 5,000. The polyalkene can comprise homopolymers or interpolymers of C.sub.2 to C.sub.16 terminal olefins, of which ethylene-propylene copolymers are said to be examples, with specific reference to a copolymer of 80% ethylene and 20% propylene.
However, ethylene-alpha-olefin copolymers of the above molecular weights could be produced using Ziegler-Natta catalysts only in combination with H.sub.2 as molecular weight control in order to terminate the growing copolymer chains within this molecular weight range. Without use of H.sub.2 or other conventional, so-called "chain stoppers", the copolymers produced with Ziegler-Natta catalysts would tend to have molecular weights greatly in excess of the above range. (Such higher copolymers, for example, are widely employed in ungrafted form as viscosity index improvers, and when grafted with nitrogen-containing groups, as described below, are conventionally employed as dispersant-viscosity index improver polymers.) The use of H.sub.2 as a chain stopper has the disadvantage of causing the saturation of the olefinic double bond content of the copolymer. Thus, while lower molecular weight copolymers were theoretically possible to prepare, their low unsaturation content (and the accompanying low graft copolymer yields) would have made their further functionalization by a thermal "ene" reaction, e.g., with dicarboxylic acid moieties in preparing dispersants, highly unattractive.
High molecular weight ethylene-propylene polymers and ethylene-propylene-diene terpolymers, having viscosity average molecular weights of from about 20,000 to 300,000, are generally produced employing Ziegler catalysts, generally VCl.sub.4 or VOCl.sub.3 with a halide source, such as organoaluminum halides and/or hydrogen halides. Such high molecular weight EP and EPDM polymers find use as viscosity index improvers. See, e.g., U.S. Pat. Nos. 3,563,964; 3,697,429; 4,306,041; 4,540,753; 4,575,574; and 4,666,619.
The concept of derivatizing V.I. improving high molecular weight ethylene copolymers, with acid moieties such as maleic anhydride, and functionalization by reaction with an amine, to form a V.I.-dispersant oil additive is known in the art as indicated by the following patents: U.S. Pat. Nos. 3,316,177; 3,326,804; 4,160,739; 4,161,452; 4,171,273; 4,517,104; 4,089,794; 4,137,185; 4,144,181; 4,219,432; 4,507,515; 4,557,847; 4,632,769; 4,693,838; and 4,707,285.
U.S. Pat. No. 4,668,834 to Uniroyal Chemical discloses preparation (via certain metallocene and alumoxane catalyst systems) and composition of ethylene-alpha olefin copolymers and terpolymers having vinylidene-type terminal unsaturation, which are disclosed to be useful as intermediates in epoxy-grafted encapsulation compositions.
Japanese Published Patent Application 87-129,303A of Mitsui Petrochemical relates to narrow molecular weight distribution (M.sub.w /M.sub.n &lt;2.5) ethylene alpha-olefin copolymers containing 85-99 mol % ethylene, which are disclosed to be used for dispersing agents, modifiers or materials to produce toners. The copolymers (having crystallinity of from 5-85%) are prepared in the presence of a catalyst system comprising Zr compounds having at least one cycloalkadienyl group and alumoxane.
European Patent 128,046 discloses (co)polyolefin reactor blends of polyethylene and ethylene higher alpha-olefin copolymers prepared by employing described dual-metallocene/alumoxane catalyst systems.
European Patent Publication 129,368 discloses metallocene/alumoxane catalysts useful for the preparation of ethylene homopolymer and ethylene higher alpha-olefin copolymers.
European Patent Application Publication 257,696 A1 relates to a process for dimerizing alpha-olefins using a catalyst comprising certain metallocene/alumoxane systems.
PCT Published Patent Application WO 88/01626 relates to transition metal compound/alumoxane catalysts for polymerizing alpha-olefins.